selection: Create it's dedicated class

includes/context.hpp

@@ -19,6 +19,8 @@ class Render;
 namespace gol {
 class SettingsMenu;
 class SelectionMenu;
+class ControlMenu;
+class Selection;
 
 typedef struct ctx {
   std::shared_ptr<World> world = nullptr;
@@ -26,6 +28,8 @@ typedef struct ctx {
   std::shared_ptr<Render> render = nullptr;
   std::shared_ptr<SettingsMenu> settings_menu = nullptr;
   std::shared_ptr<SelectionMenu> selection_menu = nullptr;
+  std::shared_ptr<ControlMenu> control_menu = nullptr;
+  std::shared_ptr<Selection> selection = nullptr;
   nlohmann::json config_json;
 } ctx;
 

includes/selection.hpp

@@ -0,0 +1,32 @@
+/*
+* File name: selection.hpp
+* Author: lejulien
+* Date created: 01-01-1970 00:59:59
+// Date modified: 12-01-2026 21:30:10
+* ------
+*/
+
+#pragma once
+
+#include <context.hpp>
+
+#include <imgui.h>
+#include <raylib.h>
+#include <rlImGui.h>
+
+namespace gol {
+
+class Selection {
+public:
+  Selection(std::shared_ptr<ctx>);
+  ~Selection() = default;
+  void update();
+  void display();
+private:
+  std::shared_ptr<ctx> context_ = nullptr;
+  Vector2 sel_pos_ = {0., 0.};
+  Vector2 mouse_pos_ = {0., 0.};
+  bool selecting_ = false;
+};
+
+} // namespace gol

includes/snapping.hpp

@@ -0,0 +1,24 @@
+/*
+* File name: selection.cpp
+* Author: lejulien
+* Date created: 01-01-1970 00:59:59
+// Date modified: 12-01-2026 21:30:10
+* ------
+*/
+
+#pragma once
+
+#include <types.hpp>
+
+#include <raylib.h>
+#include <cmath>
+
+Vector2 snapToGrid(Vector2 screen, int cell_size) {
+  return {static_cast<float>(round(screen.x / cell_size) * cell_size),
+          static_cast<float>(round(screen.y / cell_size) * cell_size)};
+}
+
+Vector2i screenToGrid(Vector2 screen, int cell_size) {
+  return {static_cast<int>(round(screen.x / cell_size)),
+          static_cast<int>(round(screen.y / cell_size))};
+}